Figure 8.

Conventional DC form cellular networks within early bronchovascular infiltrates in the lungs of CCR2^+/+ mice infected with C. neoformans. CCR2^+/+ (A–D, G, H) and CCR2^−/− (E, F) mice were inoculated IT with C. neoformans and lungs were harvested at day 10 post-infection. Samples were snap-frozen and later stained with either isotype contols (A), anti-CD11c (red peroxidase reaction product) and anti-MHC Class II (I-A^d; black alkaline phosphatase reaction product) (B–F), or anti-CD11c (red) and anti-CD11b (black) (G–H). (A) isotype control staining (×100 magnification). (B) Dendritic cell (DC) expressing both MHC Class II and CD11c (note reddish-gray color), and displaying branching cytoplasmic extensions is identified adjacent to a visible C. neoformans (CN) (×1000). Also depicted is a CD11c-expressing macrophage (M) (note strong red staining and vacuolated appearance) which has ingested a C. neoformans. (C) Photomicrograph (×200) taken from a CCR2^+/+ mouse demonstrating a scaffold-like network of DC within a bronchovascular infiltrate (BVI) adjacent an airway (AW). (D) Higher power (×400) image further identifying DC (block arrowheads). (E) Photomicrograph (×200) from a CCR2^−/− mouse confirms the paucity of DC and demonstrates that the majority of CD11c positive (red) cells within these infiltrates are macrophages (arrows). (F) Higher power (×400) image confirms macrophage morphology of these CD11c positive cells (arrows), many of which have ingested C. neoformans. (G) Photomicrograph (×200) from a CCR2^+/+ mouse co-stained with CD11c (red) and CD11b (black) depicting a dense bronchovascular infiltrate. (H) Higher power (×400) image reveals that numerous cells with branching cytoplasmic extensions express both CD11c and CD11b (arrows, note reddish-gray color) confirming their cDC phenotype.